This invention relates to a cathode ray tube device used with a display system suitable for a giant color display.
In the conventional construction of giant display systems, for example, electric light display boards used with baseball fields, apparatus for displaying advertising pictures or the like on the roof top or wall surface of buildings, etc., pictures have been formed by selectively effecting the turn-on and-off of a multitude of colored electric lamps arranged in a predetermined pattern. Such display systems have had many difficult problems to be solved. For example, it could be first mentioned that the color retention is poor. This has originally resulted from the fact that the electric lamps bring out colors by having their filaments heated to red heat and assume the red or while orange color. Therefore, in order to produce separately three colors or red, green and blue required for colored pictures to be reproduced, light beams emitted from the respective filaments have been picked up after colored glass plates or the like have been used to separate the light beams into red, green and blue components and selecting them. However, as the electric lamp serving as a light source is naturally little in its quantity of the green component and particularly of the blue component, it has been very difficult to pick up those colors. Also, when the electric lamps arranged as described above are selectively turned on and off, the brightness modulation of each picture element or each electric lamp has been required to rely on means for turning a current applied to the mating filament on and off or of rendering the applied current variable. Furthermore such means has had a frequency response as low as 10 hertz or less and, in addition, the intermediate color tone has been permitted to be displayed only in two or three steps. Furthermore, electric lamps on the order of 12 watts have been generally employed and each of display systems has included, for example, several ten thousand of such electric lamps. This has encountered many problems in a power consumption, heat generated by the individual electric lamps, the reliability, maintenance etc.
Accordingly, it is a general object of the present invention to solve the problems as described above.
It is an object of the present invention to provide a new and improved cathode ray tube device for a display system excellent in color retention, and extremely low in power consumption, resulting in the high performance and the power saving type.
It is another object of the present invention to provide a new and improved cathode ray tube device for a display system high in both security and reliability and easy in maintenance.